Collar and shaft assembly

ABSTRACT

A collar and shaft assembly utilizing a ring and a multi-stepped groove. The multi-stepped groove permits the ring to be compressed into one groove while the collar is being assembled and then to expand into a different groove that permits the ring to contact surfaces on both the collar and the shaft.

CROSS REFERENCE TO RELATED APPLICATIONS AND CLAIM OF PRIORITY

The present application is a divisional of and claims priority under 35U.S.C. § 120 to commonly assigned, U.S. Pat. No. 10,954,984, entitledCOLLAR AND SHAFT ASSEMBLY, issued Mar. 23, 2021, which claims thepriority benefits under the provisions of 35 U.S.C. § 119, basing saidclaim of priority on related U.S. Provisional Application No. 62/428,008filed Nov. 30, 2016, both of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

The present invention relates to a collar and shaft assembly and thelike, and in particular to a shaft with a snap on collar. This collarand shaft assembly can be used for a variety of purposes, including inmetal forming dies.

Shafts with collars can be used for a variety of purposes. For example,they can be used to provide a positive stop between components with thecollar acting as a shoulder to abut the surface of another component.One example of this is in metal forming dies. Metal forming dies, suchas stamping dies and the like, are well-known in the art. Progressivemetal forming dies are unique, very sophisticated mechanisms which havemultiple stations or progressions that are aligned longitudinally andare designed to perform a specified operation at each station in apredetermined sequence to create a finished metal part. Progressivestamping dies are capable of forming complex metal parts at very highspeeds, so as to minimize manufacturing costs.

Heretofore, the dies used in metal forming presses have typically beenindividually designed, one-of-a-kind assemblies for a particular part,with each of the various components being handcrafted and custom-mountedor fitted in an associated die set, which is in turn positioned in astamping press. Not only are the punches and the other forming tools inthe die set individually designed and constructed, but the other partsof the die set, such as stock lifters, guides, end caps and keepers, camreturns, etc., are also custom designed, and installed in the die set.Current die making processes require carefully machined, precision holesand recesses in the die set for mounting the individual components, suchthat the same are quite labor intensive and require substantial leadtime to make, test, and set up in a stamping press. Consequently, suchmetal forming dies are very expensive to design, manufacture, and repairor modify.

It would be further advantageous to have a collar and shaft assemblythat can be used in a die or other situation that requires a collar witha shoulder that can receive a large force without breaking or shearingthe assembly. It would be also advantageous to have a collar andshoulder assembly that is easy to assemble but stays connected to theshaft over time.

SUMMARY OF THE INVENTION

One aspect of the present invention is a collar and shaft assembly. Thecollar and shaft assembly includes a shaft having a generallycylindrical shape with a first end portion, a second end portion, and astepped groove. The collar and shaft assembly includes a collar having agenerally cylindrical shape with a first end portion, a second endportion, and an aperture that extends through the collar with a firstgenerally cylindrical inner sidewall, and a second generally taperedinner sidewall. A groove extends about the interior surface of the firstgenerally cylindrical inner sidewall. The collar and shaft assembly alsoincludes a retainer ring that is closely received and retained in thestepped groove in the shaft and the groove on the collar.

Yet another aspect of the present invention is a collar and shaftassembly that includes a shaft having a generally cylindrical shape, afirst end portion, a second end portion, and a retainer ring groove onthe exterior surface of the shaft. The collar and shaft assemblyincludes a collar having generally cylindrical shape with a first endportion, a second end portion, an aperture that extends through thecollar, and a stepped groove extending circumferentially above theinterior surface of the aperture in the collar. The collar and shaftassembly also includes a retainer ring closely received and retained inthe stepped groove in the collar and in the retainer ring groove on theshaft.

Yet another aspect of the present invention is a method for making acollar and shaft assembly. The method includes forming a shaft with afirst end portion, a second end portion, and a stepped groove extendingcircumferentially about an exterior surface of the shaft. The steppedgroove includes a first portion with a first groove depth and a secondportion with a second groove depth that is less than the first groovedepth. The method includes forming a collar with a first end portion, asecond end portion, and an aperture that extends through the collarhaving a first generally cylindrical inner sidewall, and a secondgenerally tapered inner sidewall. The method includes providing aretainer ring to be closely received in the stepped groove. The methodfurther includes advancing the collar over the shaft until the generallytapered portion of the collar engages and compresses the retainer ringinto the first portion of the stepped groove and then further advancingthe collar over the shaft until the retainer ring expands and is seatedin between the second portion of the stepped groove on the shaft and thegroove on the collar.

These and other advantages of the invention will be further understoodand appreciated by those skilled in the art by reference to thefollowing written description, claims, and appended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a fragmentary view of a collar and shaft assembly embodyingthe present invention;

FIG. 2 is an exploded perspective view of the collar and shaft assemblyshown in FIG. 1;

FIG. 3 is a fragmentary, cross-sectional view of the collar and shaftassembly with the collar assembled on the shaft;

FIG. 4. is a partial cross-sectional view of one preferred sequence forassembling the collar and shaft assembly shown in FIGS. 1-3;

FIG. 5 is a fragmentary, cross-sectional view of the collar and shaftassembly of FIG. 1 showing a directional force on the collar and shaftassembly;

FIG. 6 is a fragmentary, cross-sectional view of the collar and shaftassembly showing a directional force on the collar and shaft assembly;

FIG. 7 is a fragmentary, cross-sectional view, taken along line VII ofFIG. 6, showing a directional force on the collar and shaft assembly;

FIG. 8 is a pair of cross-sectional views of the collar and shaftassembly showing the resulting forces on the lower and upper sides ofthe collar and shaft assembly;

FIG. 9 is a pair of fragmentary, cross-sectional views of the collar andshaft assembly illustrating the sliding of the collar on the shaft whenthe collar is not press fit on the shaft, as illustrated in the upperfigure;

FIG. 10 is a top perspective view of the collar shown in FIG. 1;

FIG. 11 is a cross-sectional view of the collar;

FIG. 12 is a partial side perspective view of the shaft shown in FIG. 1;

FIG. 13 is a partial cross-sectional view of the shaft;

FIG. 14 illustrates another embodiment of the collar and shaft assemblywherein the stepped groove is located on the collar;

FIG. 15 is a partial cross-sectional view of one preferred sequence forassembling the collar and shaft assembly shown in FIG. 14;

FIG. 16 is a partial cross-sectional view of the collar and shaftassembly shown in FIG. 14 showing a directional force applied to thecollar;

FIG. 17 is another embodiment of the collar and shaft assembly utilizinga dampening member;

FIG. 18 is a partial cross-sectional view of the collar and shaftassembly shown in FIG. 17;

FIG. 19 is another embodiment of the collar and shaft assembly utilizingan additional ring for securing the collar to the shaft;

FIG. 20 is a partial cross-sectional view of the collar and shaftassembly shown in FIG. 19;

FIG. 21 is another embodiment of a collar and shaft assembly utilizinganother device for securing the collar to the shaft;

FIG. 22 is a partial cross-sectional view of the collar and shaftassembly shown in FIG. 21;

FIG. 23 is a partial cross-sectional view of another embodiment of thecollar and shaft assembly utilizing a locating device to help secure thelocation of the collar on the shaft;

FIG. 24 is a partial cross-sectional view of the collar and shaftassembly shown in FIG. 23;

FIG. 25 is a partial cross-sectional view of another embodiment of acollar and shaft assembly utilizing another locating device to helpsecure the collar on the shaft;

FIG. 26 is a partial cross-sectional view of the collar and shaftassembly shown in FIG. 25;

FIG. 27 is a partial cross-sectional view of another embodiment of acollar and shaft assembly utilizing a cap on the collar; and

FIG. 28 is a partial cross-sectional view of the collar and shaftassembly shown in FIG. 27.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

For purposes of description herein, the terms “upper,” “lower,” “right,”“left,” “rear,” “front,” “vertical,” “horizontal,” and derivativesthereof shall relate to the invention as oriented in FIGS. 1-28.However, it is to be understood that the invention may assume variousalternative orientations and step sequences, except where expresslyspecified to the contrary. It is also to be understood that the specificdevices and processes illustrated in the attached drawings, anddescribed in the following specification, are simply exemplaryembodiments of the inventive concepts defined in the appended claims.Hence, specific dimensions and other physical characteristics relatingto the embodiments disclosed herein are not to be considered aslimiting, unless the claims expressly state otherwise.

The reference numeral 2 (FIGS. 1, 2) generally designates a collar andshaft assembly embodying the present invention. The collar and shaftassembly 2 includes a collar 4 with an aperture 6. Aperture 6 can be agenerally cylindrical through-hole, as illustrated in FIG. 2. The collar4 has a first end 16 and a second end 18 with the generally cylindricalaperture 6 extending between the first end 16 and the second end 18. Thecollar 4 also has a tapered portion 12 located at the second end 18 ofthe collar 4. A groove 14 is located in the interior of the aperture 6,as illustrated in FIG. 2.

The collar and shaft assembly 2 also has a shaft 20 with a first end 22and a second end 24. The shaft has a stepped groove 26 with a firstportion 28 and a second portion 30, as illustrated in FIG. 13. Thesecond portion 30 has a depth that is greater than the depth of thefirst portion 28, as illustrated in FIGS. 3 and 13.

A retainer 40 is used to connect the collar 4 and the shaft 20, asillustrated in FIG. 1. The retainer 40 in the illustrated embodiment isa metal C-ring. However, any type of retainer can be used to fix thelocation of the collar 4 on the shaft 20 provided the retainer canexpand and contract and ultimately be retained in between the firstportion 28 of the stepped groove 26 and the groove 14 of the collar 4.

The steps for creating the assembly 2 are shown in FIG. 4. The firststep involves loading the retainer 40 over the shaft 20. In the secondstep, the retainer 40 is snapped into the stepped groove 26. The thirdstep involves loading the collar 4 over the shaft 20 by applying forcein the direction shown by the arrows in FIG. 4. The fourth step involvesthe tapered portion 12 of the collar 4 capturing and centering theretainer 40. The fifth step involves the tapered portion 12 of thecollar 4 compressing the retainer 40 into the second portion 30 of thestepped groove 26 shown by the arrows R, while the collar is moved inthe direction shown by the arrows F. The sixth step involves sliding thecollar 4 over the shaft 20 until the stepped groove 26 of the shaft 20and the groove 14 of the collar 4 are aligned. As illustrated in theseventh step, when the grooves 26, 14 are aligned, the retainer 40expands into the groove 14 on the collar 4, as shown by the arrows R. Inthe eighth step, the collar 4 is then shifted backwards in direction, asshown by arrows F, until the collar 4 stops with the retainer 40 in thefirst portion 28 of the stepped groove 26 of shaft 20 and the groove 14of collar 4.

As illustrated in FIG. 5, when force F is applied, the resultant forcesare transferred through the retainer 40 into the shaft 20. In thisarrangement, the retainer 40 is seated into the groove 14 in the collar4 and into the first portion 28 of the stepped groove 26 of the shaft 20with no voids.

As illustrated in FIGS. 6 and 7, the working forces F against the secondend 18 of collar 4 are transferred through the retainer 40 to the shaft20 and collar 4. The retainer 40 has a high sheer strength and providesa strong transfer of forces from the collar 4 to the shaft 20. This isparticularly true where the retainer 40 is a steel C-ring. Asillustrated in FIG. 8, the collar and shaft assembly 2 is a permanentand potentially tamper-proof assembly. The retainer 40 is undercompression and is always trying to expand into the groove 14 of thecollar 4. The illustrated design prevents the compression of theretainer 40 back into second portion 30 of the stepped groove 26 in theshaft 20 thereby preventing removal of the collar 4. No matter whichdirection the collar 4 is forced, as illustrated by arrows F, theretainer 40 cannot be compressed in a manner to permit the removal ofthe collar 4 from the shaft 20.

As illustrated in FIG. 9, due to the small void v created by the firstand second portions 28, 30 of stepped groove 26, the collar 4 can movealong the shaft 20 creating a nonstationary position of the collar 4. Toprevent the collar 4 from moving along the shaft 20, the fit between theoutside diameter 31 of the shaft 20, as illustrated in FIG. 2, and theinside diameter 15 of the collar 4 can be substantially the same suchthat there is a press-fit interference between the collar 4 and theshaft 20. Such a press-fit will minimize the ability of the collar 4 tomove on the shaft 20 if needed or desired.

As illustrated in FIG. 10, the collar 4 can have a tapered portion 12near the second end 18. The collar 4 can be formed by a simple turningon a lathe. Similarly, the shaft 20 can be formed by a simple turning ona lathe in order to create the first and second portions 28, 30 of thestepped groove 26.

Another embodiment is illustrated in FIG. 14 with the single groove 126on shaft 120 and the stepped groove 114 on the collar 104. The steppedgroove 114 on the collar 104 has a first portion 117 and a secondportion 115, with a smaller groove depth. The stepped groove 114 islocated generally between the first end 116 and the second end 118 ofthe collar 104.

As illustrated in FIG. 15, the first assembly step is the loading of theretainer 140 onto collar 104. Next, the retainer 140 expands into thestepped groove 114. The third step involves loading the collar 104 overthe shaft 120 by applying force, as shown in arrows F. Next the shaft120 captures the retainer 140. This can be accomplished by having ataper 119 formed on the shaft 120, as illustrated in step 5. The taper119 expands the retainer 140 into the stepped groove 114 on collar 104.The sixth step involves sliding the collar 104 until the grooves 114 and126 generally align. The seventh step illustrates that when the grooves114, 126 align, the retainer 140 collapses into the groove 126 in shaft120. The last step involves shifting the collar 104 back as illustratedby arrows F until the collar 104 stops with the retainer 140 closelyreceived in the second portion 115 of the stepped groove 114 in thecollar 104 and the groove 126 in shaft 120.

As illustrated in FIG. 16, when force F is applied, the retainer 140remains seated in the groove 114 on the collar 104. The forces aretransferred through the retainer 140 into the shaft 120 and collar 104.

A dampening device can be added to the collar and shaft assembly 2, asillustrated in FIGS. 17 and 18. A stop disk 42 can be added to preventthe collar 4 from directly contacting the shaft 20, as illustrated inFIG. 17. The stop disk 42 contacts a shoulder 32 formed on the shaft 20.In addition, a reaction device 44 can be situated between the stop disk42 and a shoulder 45 that is formed on the collar 4, as illustrated inFIG. 17. This reaction device 44 can also be situated directly betweenthe collar 4 and the shaft 20 without the presence of a stop disk 42.The reaction device 44 can be any device that would provide a dampeningfunction, such as an elastomeric material and/or a spring. Asillustrated in FIG. 18, when force F is applied, the reaction device 44pushes against the shoulder 45 on the collar 4, keeping the collar 4 inplace while the stop disk 42 abuts the shoulder 32 on the shaft 20.

Additional embodiments include different ways of preventing movement ofthe collar 4 with respect to the shaft 20. As illustrated in FIG. 19, aretaining ring 46 can be included to retain the collar 4 on the shaft20. Specifically, the retaining ring 46 is received in a second groove50 in collar 4 that is located near the first end 16 of the collar 4.This groove 50 can include a tapered portion 53 to permit thecompression of the retaining ring 46 to fit into and expand in groove50. As illustrated in FIGS. 21 and 22, a C-ring 48 can be used into fitinto a groove 51 located near the first end 16 of the collar 4 torestriction the movement of the collar 4 on the shaft 20.

As illustrated in FIGS. 23 and 24, an alignment member 52 can beinserted through an opening 54 in the collar 4 and into an opening 56 inthe shaft 20 to prevent movement of the collar 4 on the shaft 20. Thealignment member 52 can be a dowel with a seam 58 such that the dowelcan expand once it has been inserted into the aligned openings 54, 56,as illustrated in FIG. 24. Openings 54 and 56 should be of a similardiameter and generally align when the retainer 40 is seated in the firstportion 28 of the stepped groove 26 on the shaft 20 and the groove 14 ofcollar 4.

In another embodiment, a steel ball 60 can be placed through an opening62 in the collar 4 to fit into opening 64 in the shaft 20. The ball 60should be press-fit into such openings 62, 64 and should situate theball 60 to prevent movement of the collar 4 with respect to shaft 20. Inparticular, the opening 64 in the shaft 20 should be smaller in depththan the diameter of the ball 60 so that the ball 60 contacts surfacesin both openings 62, 64, as illustrated in FIG. 26.

In another embodiment, the collar 70 has a cap 72 with an opening 76. Areaction device 74 can be located between the first end 22 of the shaft20 and the cap 72 of the collar 70. The reaction device 74 can be aspring, elastomeric member, or other device. In the embodimentillustrated in FIGS. 27 and 28, the reaction device 74 is an elastomericO-ring. As illustrated in FIG. 28, when force F is applied, the reactiondevice 74 is partially compressed to keep the collar 70 in place. In theembodiment illustrated in FIGS. 27 and 28, the collar 70 is located atone end of the shaft 20. This is an example of how a collar 4, 70 can belocated at either end of the shaft 20 with or without a cap 72. Inaddition, more than one collar 4, 70 can be used on a single shaft 20.

In the foregoing description, it will be readily appreciated by thoseskilled in the art that modifications may be made to the inventionwithout departing from the concepts disclosed herein. Such modificationsare to be considered as included in the following claims, unless theseclaims by their language expressly state otherwise.

It will be understood by one having ordinary skill in the art thatconstruction of the present disclosure and other components is notlimited to any specific material. Other exemplary embodiments of thedisclosure disclosed herein may be formed from a wide variety ofmaterials, unless described otherwise herein.

For purposes of this disclosure, the term “coupled” or “operablycoupled” (in all of its forms, couple, coupling, coupled, etc.)generally means the joining of two components (electrical or mechanical)directly or indirectly to one another. Such joining may be stationary innature or movable in nature. Such joining may be achieved with the twocomponents (electrical or mechanical) and any additional intermediatemembers being integrally formed as a single unitary body with oneanother or with the two components. Such joining may be permanent innature or may be removable or releasable in nature unless otherwisestated.

For purposes of this disclosure, the term “connected” or “operablyconnected” (in all of its forms, connect, connecting, connected, etc.)generally means that one component functions with respect to anothercomponent, even if there are other components located between the firstand second component, and the term “operable” defines a functionalrelationship between components.

It is also important to note that the construction and arrangement ofthe elements of the present disclosure as shown in the exemplaryembodiments is illustrative only. Although only a few embodiments of thepresent innovations have been described in detail in this disclosure,those skilled in the art who review this disclosure will readilyappreciate that, unless otherwise described, many modifications arepossible (e.g., variations in sizes, dimensions, structures, shapes andproportions of the various elements, values of parameters, mountingarrangements, use of materials, colors, orientations, etc.) withoutmaterially departing from the novel teachings and advantages of thesubject matter recited. For example, elements shown as integrally formedmay be constructed of multiple parts or elements shown as multiple partsmay be integrally formed, the operation of the interfaces may bereversed or otherwise varied, the length or width of the structuresand/or members or connector or other elements of the system may bevaried, the nature or number of adjustment positions provided betweenthe elements may be varied. It should be noted that the elements and/orassemblies of the system may be constructed from any of a wide varietyof materials that provide sufficient strength or durability, in any of awide variety of colors, textures, and combinations. Accordingly, allsuch modifications are intended to be included within the scope of thepresent innovations. Other substitutions, modifications, changes, andomissions may be made in the design, operating positions, andarrangement of the desired and other exemplary embodiments withoutdeparting from the spirit of the present innovations.

It will be understood that any described processes or steps withindescribed processes may be combined with other disclosed processes orsteps to form structures within the scope of the present disclosure. Theexemplary structures and processes disclosed herein are for illustrativepurposes and are not to be construed as limiting.

It is also to be understood that variations and modifications can bemade on the aforementioned structures and methods without departing fromthe concepts of the present invention, and further it is to beunderstood that such concepts are intended to be covered by thefollowing claims unless these claims by their language expressly stateotherwise.

The invention claimed is:
 1. A collar and shaft assembly, comprising: ashaft having a generally cylindrical shape with a generally uniformdiameter, comprising: a first end portion; a second end portion; and aretainer ring groove extending circumferentially about the exteriorsurface of the shaft; a collar having a generally cylindrical shape,comprising: a first end portion; a second end portion; a medial portionpositioned in between said first end portion and said second endportion; an aperture that extends through the collar having an innersurface; and a stepped groove extending circumferentially about theinner surface of said aperture in said collar in said medial portion ofsaid collar, away from said first end portion and said second endportion such that no portion of the stepped groove extends to said firstend portion or said second end portion; and a retainer ring received andretained in said stepped groove in said collar and the retainer ringgroove on said shaft.
 2. The collar and shaft assembly as set forth inclaim 1, wherein said retainer ring is a metal C-ring.
 3. The collar andshaft assembly as set forth in claim 1, wherein said stepped groove onsaid collar is located between said first end portion and said secondend portion of said collar.
 4. The collar and shaft assembly as setforth in claim 1, wherein said stepped groove on said collar includes afirst portion with a first groove depth and a second portion with asecond groove depth that is less than said first groove depth.
 5. Thecollar and shaft assembly as set forth in claim 4, wherein said firstportion of said stepped groove is located on the portion of the steppedgroove that is closest to the first end portion of said collar.
 6. Thecollar and shaft assembly as set forth in claim 1, wherein said aperturein said collar includes a tapered section.
 7. The collar and shaftassembly as set forth in claim 6, wherein said tapered section islocated in said aperture at said second end portion of said collar. 8.The collar and shaft assembly as set forth in claim 1, wherein saidshaft includes a narrowed section at said first end portion.
 9. Thecollar and shaft assembly as set forth in claim 8, wherein said narrowedsection is tapered.
 10. The collar and shaft assembly as set forth inclaim 8, wherein said narrowed section includes a groove.
 11. A methodof making a collar and shaft assembly, comprising: forming a generallycylindrical shaft with a generally uniform diameter, including: a firstend portion; a second end portion; and a retainer ring groove extendingcircumferentially about the exterior surface of the shaft; forming agenerally cylindrical collar with a generally uniform outer diameter,including: a first end portion; a second end portion; a medial portionpositioned in between said first end portion and said second endportion; an aperture that extends through the collar having an innersurface; and a first generally cylindrical stepped groove in said medialportion of said collar, away from said first end portion and said secondend portion such that no portion of the stepped groove extends to saidfirst end portion or said second end portion, that extendscircumferentially about the inner surface with a wider portion of saidstepped groove oriented toward said first end portion and the narrowerportion of said stepped groove oriented toward said second end portion;positioning a retainer ring in said stepped groove; advancing the secondend portion of that collar over said first end portion of said shafttoward said second end of said shaft, such that the narrower portion ofsaid stepped grooce is advanced over said shaft before said widerportion of said stepped groove; until said retainer ring is received insaid retainer ring groove in said shaft and in said narrower portion ofsaid stepped groove in said collar.
 12. The method of making a collarand shaft assembly of claim 11, wherein said stepped groove is locatedbetween said first end portion and said second end portion of saidcollar.
 13. The method of making a collar and shaft assembly of claim11, wherein said aperture in said collar includes a generally taperedinner surface located near said second end portion of said collar. 14.The method of making a collar and shaft assembly of claim 11, whereinsaid shaft includes a narrowed surface near said first end portion ofsaid shaft.
 15. The method of making a collar and shaft assembly ofclaim 14, wherein providing a retainer ring at said first end portion ofsaid shaft includes providing said retainer ring in said narrowedsurface.
 16. The method of making a collar and shaft assembly of claim11, wherein said retainer ring is a metal C-ring.
 17. The method ofmaking a collar and shaft assembly of claim 11, wherein said retainerring groove extends about the entire exterior surface of the shaft. 18.The method of making a collar and shaft assembly of claim 11, whereinsaid stepped groove extends about the entire inner surface of saidaperture in said collar.
 19. The method of making a collar and shaftassembly of claim 18, wherein said stepped groove includes a firstportion with a first groove depth located nearer to said first endportion of said collar and a second portion with a second groove depththat is less than said first groove depth located nearer to said secondend portion of said collar.
 20. A collar and shaft assembly, comprising:a shaft having a generally cylindrical shape with a generally uniformdiameter, comprising: a first end portion with a narrowed section; asecond end portion; and a retainer ring groove extendingcircumferentially about the exterior surface of the shaft between saidfirst end portion and said second end portion; a collar having agenerally cylindrical shape, comprising: a first end portion; a secondend portion; a medial portion in between said first end portion and saidsecond end portion; an aperture that extends through the collar havingan inner surface; and a stepped groove extending circumferentially aboutthe inner surface of said aperture in said medial portion of saidcollar, away from said first end portion and said second end portionsuch that no portion of the stepped groove extends to said first endportion or said second end portion; and a retainer ring received andretained in said stepped groove in said collar and the retainer ringgroove on said shaft.